1. Field of the Invention
The present invention relates to a thermistor element.
2. Description of the Related Art
Conventionally, thermistor elements include one described in Japanese Patent No. 4985989. The thermistor elements each include a body, multiple internal electrodes laminated within the body, and first and second external electrodes provided on both ends of the body.
In this regard, the shortest distance between the first external electrode and the outermost internal electrode with a polarity different from the polarity of the first external electrode, which is disposed outermost in the laminating direction, is referred to as a first distance d. The shortest distance between two internal electrodes that are adjacent in the laminating direction and different in polarity from each other is referred to as a second distance t. In this case, the distances satisfy d/t≤0.96.
As just described, the first distance d being smaller than the second distance t causes selective discharge between the first external electrode and the outermost internal electrode because the first distance d is short, when a high voltage is applied to the body. Japanese Patent No. 4985989 mentions therein that the body will thus never be broken, in the absence of discharge between the internal electrodes that differ in polarity.
Now, when the conventional thermistor element is actually manufactured and used, the thermistor element may vary in resistance from one product to another.
Considering the cause thereof, the lengths of the external electrodes vary from one product to another in a direction perpendicular to both end surfaces of the body. More specifically, the first distance d varies from one product to another. In addition, because the first distance d is short, the resistance is low between the first external electrode and the outermost internal electrode, thus increasing the contribution ratio of the resistance between the first external electrode and the outermost internal electrode to the resistance of the whole product.
Accordingly, when the first distance d varies from one product to another, the resistance between the first external electrode and the outermost internal electrode varies from one product to another, and as a result, the thermistor element resistance varies from one product to another.